A marijuana cart (short for cartridge) is a small, pre-filled container of cannabis oil designed to attach to a battery-powered vape pen. When you press a button or simply inhale, the battery heats a tiny coil inside the cartridge, turning the thick oil into vapor you breathe in. Carts have become one of the most popular ways to consume cannabis because they’re portable, discreet, and don’t produce the smoke or smell of traditional flower.
How a Cart Is Built
Every cartridge has four basic parts. The mouthpiece sits at the top and is usually made from plastic, metal, or ceramic. Below it is the tank, a small transparent chamber (typically glass) that holds the cannabis oil so you can see how much is left. At the bottom of the tank sits the atomizer, which contains a heating coil that vaporizes the oil. And at the very base is the threaded connector that screws into your battery.
Most cartridges use what’s called a 510-thread connection, an industry standard named after the size of the threading. If you buy a battery and a cartridge separately, both need to be 510-threaded or they won’t fit together. You can safely assume most batteries and carts on the market use this standard unless the packaging says otherwise.
What’s Inside the Oil
The oil in a cart is a concentrated cannabis extract, and the type of extract determines the flavor, potency, and overall experience. The two most common types are distillate and live resin.
Distillate goes through heavy refinement to isolate THC, stripping away nearly everything else in the process. The result is a high-purity oil that’s almost flavorless on its own. Manufacturers typically add terpenes back in afterward to create flavor. These added terpenes can come from cannabis plants or from botanical sources, and the difference is noticeable: botanical blends often taste simpler and less “weedy” than cannabis-derived ones.
Live resin takes a different approach. The cannabis plant is flash-frozen right after harvest, which preserves the volatile terpenes and minor cannabinoids that normally break down during drying. The extraction process is designed to keep that broad chemical profile intact. Live resin carts tend to have layered, strain-specific flavors that more closely resemble the original plant. They’re generally priced higher than distillate carts for this reason.
You may also see labels like “full spectrum” or “HTFSE” (high terpene full spectrum extract), which indicate oils that retain a wide range of the plant’s natural compounds rather than isolating a single cannabinoid.
How Potent Are Carts?
Cannabis carts are significantly stronger than flower. Traditional dried cannabis averages around 21% THC, while concentrates used in cartridges typically range from 60% to 90% THC. That’s roughly three to four times the concentration of what you’d find in a joint or bowl. This is worth knowing if you’re new to cannabis or switching from flower to carts, because a single puff delivers considerably more THC than you might expect.
Disposable Pens vs. Standard Carts
There are two main formats. A standard 510-thread cartridge is just the top half of the equation. You buy a reusable battery separately, charge it, then screw on your cartridge. When the cart is empty, you toss it and attach a new one. The battery lasts about a year or longer before it stops holding a charge, which makes this option cheaper over time and better for the environment.
A disposable vape pen is an all-in-one device: battery, oil, and mouthpiece in a single unit. It comes pre-charged and ready to use out of the box, usually activated just by inhaling. When the oil runs out, you throw the whole thing away. Disposables are more convenient and a common first purchase for beginners, but they generate more waste and can be harder to recycle.
Ceramic vs. Metal Heating Elements
The coil inside the atomizer is made from either metal or ceramic, and the material matters more than you might think. Metal coils, especially in cheaply made cartridges, can corrode over time as the acidic cannabis oil breaks down the metal surface. This process, called leaching, allows compounds like lead, nickel, and chromium to seep into the oil and eventually into the vapor you inhale. Dry hits from metal coils also tend to produce a harsh, burnt taste.
Ceramic coils are more porous, which means they absorb oil more evenly and heat it across a larger surface area. This produces fuller flavor and denser vapor while using less oil per puff. Ceramic is also resistant to the corrosion that affects metal, so it doesn’t carry the same leaching risk. If you’re comparing two similar carts at different price points, the ceramic option is generally worth the extra cost.
Safety and What to Look For
The biggest safety concerns with carts come from unregulated products. During the 2019 EVALI outbreak (a wave of vaping-related lung injuries), vitamin E acetate was identified in illicit cartridges as a key culprit. It had been used as a cheap thickening agent and is now banned from legal cannabis products in many states. Other additives found in counterfeit or low-quality carts include medium-chain triglycerides (MCT oil), propylene glycol, and vegetable glycerin, all used to thin or stretch the oil.
In regulated markets, every cartridge batch must pass laboratory testing before it reaches shelves. These tests check for THC and CBD potency, pesticide residues, heavy metals like lead and mercury, microbial contaminants such as E. coli and salmonella, and residual solvents like butane or ethanol left over from extraction. The results are documented in a Certificate of Analysis, or COA, which reputable brands make available on their website or packaging.
Research has also shown that even legal cartridge hardware can leach metals into the oil over time. Factors that increase this risk include higher operating temperatures, longer storage periods, and low oil levels that expose the coil to more direct heat. Cannabis oil is naturally acidic, and prolonged contact between the oil and metal components causes gradual corrosion. One study found that levels of copper, chromium, nickel, and lead increased significantly in cartridges stored for longer periods, especially at higher temperatures.
Keeping Your Cart Working Well
Clogged airflow is the most common annoyance with cartridges. Oil thickens in cold temperatures and can block the narrow airway inside the mouthpiece. To prevent this, store your cart upright in a cool, dry place away from direct sunlight. Avoid leaving it in a hot car or a freezing garage, since extreme temperatures change the oil’s consistency and can cause leaks or uneven vaporization.
If your cart does clog, detach it from the battery first. Use a toothpick or thin pin to gently clear any hardened oil from the airway. You can also hold the cart near a gentle heat source like a hairdryer for a few seconds to soften the blockage. Wiping down the mouthpiece and the threaded connection point with a cotton swab dipped in isopropyl alcohol every so often helps prevent residue buildup that contributes to clogs over time.